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Description: Define the function for the absolute value (modulus) of a complex number. See abscli for its closure and absval or absval2i for its value. For example, ( abs-u 2 ) = 2 ( ex-abs ). (Contributed by NM, 27-Jul-1999)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-abs | ⊢ abs = ( 𝑥 ∈ ℂ ↦ ( √ ‘ ( 𝑥 · ( ∗ ‘ 𝑥 ) ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cabs | ⊢ abs | |
| 1 | vx | ⊢ 𝑥 | |
| 2 | cc | ⊢ ℂ | |
| 3 | csqrt | ⊢ √ | |
| 4 | 1 | cv | ⊢ 𝑥 |
| 5 | cmul | ⊢ · | |
| 6 | ccj | ⊢ ∗ | |
| 7 | 4 6 | cfv | ⊢ ( ∗ ‘ 𝑥 ) |
| 8 | 4 7 5 | co | ⊢ ( 𝑥 · ( ∗ ‘ 𝑥 ) ) |
| 9 | 8 3 | cfv | ⊢ ( √ ‘ ( 𝑥 · ( ∗ ‘ 𝑥 ) ) ) |
| 10 | 1 2 9 | cmpt | ⊢ ( 𝑥 ∈ ℂ ↦ ( √ ‘ ( 𝑥 · ( ∗ ‘ 𝑥 ) ) ) ) |
| 11 | 0 10 | wceq | ⊢ abs = ( 𝑥 ∈ ℂ ↦ ( √ ‘ ( 𝑥 · ( ∗ ‘ 𝑥 ) ) ) ) |